Suction valves which can be manually actuated via a push button are used in endoscopes, fiberscopes and other medical instruments to evacuate body secretions, irrigation fluid, or likewise from body cavities.
The suction valves disclosed in DE 29 54 069 C2 and EP 0 106 310 B1 have complicated structures since they must be gas-tight and liquid-tight. The valves include actuation elements which are designed like pistons and sealed to the housing by O-rings or similar. The O-rings are arranged on the piston-like actuation elements and at the same time are displaced axially within the valve housing. This arrangement causes friction and eventually leakage of the valves due to friction. Further, a disadvantage with these complicated valves is that they cannot be cleaned sufficiently or cleaned only with much effort. Additionally, they are expensive and time-consuming to manufacture.